TWCUX vs. PLFMX

Last updated Jun 24, 2026

TWCUX (American Century Ultra Fund) and PLFMX (Principal LargeCap S&P 500 Index Fund) are both mutual funds - TWCUX is a Large Cap Growth Equities fund managed by American Century, while PLFMX is a S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, TWCUX returned 18.08%/yr vs 15.12%/yr for PLFMX. Their correlation of 0.93 suggests significant overlap in exposure. TWCUX charges 0.93%/yr vs 0.72%/yr for PLFMX.

Performance

TWCUX vs. PLFMX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century Ultra Fund (TWCUX) and Principal LargeCap S&P 500 Index Fund (PLFMX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, TWCUX achieves a 3.79% return, which is significantly lower than PLFMX's 9.46% return. Over the past 10 years, TWCUX has outperformed PLFMX with an annualized return of 18.08%, while PLFMX has yielded a comparatively lower 15.12% annualized return.

TWCUX

• 1D: -1.43%
• 1M: -3.17%
• YTD: 3.79%
• 6M: 2.38%
• 1Y: 18.43%
• 3Y*: 18.97%
• 5Y*: 10.35%
• 10Y*: 18.08%

PLFMX

• 1D: -0.36%
• 1M: 0.06%
• YTD: 9.46%
• 6M: 8.46%
• 1Y: 24.74%
• 3Y*: 21.18%
• 5Y*: 13.13%
• 10Y*: 15.12%

*Multi-year figures are annualized to reflect compound growth (CAGR)

TWCUX vs. PLFMX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
TWCUX American Century Ultra Fund	3.79%	12.66%	29.54%	43.36%	-32.38%	23.47%	49.79%	34.60%	0.70%	31.65%
PLFMX Principal LargeCap S&P 500 Index Fund	9.46%	17.10%	26.06%	25.27%	-18.67%	27.57%	17.46%	30.58%	-5.14%	20.96%

Correlation

The correlation between TWCUX and PLFMX is 0.92, indicating a strong positive relationship between their price movements. Combining them offers limited diversification - they tend to fall together during downturns.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.92
Correlation (3Y) Calculated over the trailing 3-year period	0.91
Correlation (5Y) Calculated over the trailing 5-year period	0.93
Correlation (10Y) Calculated over the trailing 10-year period	0.91
Correlation (All Time) Calculated using the full available price history since Dec 6, 2000	0.93

The correlation between TWCUX and PLFMX has been stable across timeframes, ranging from 0.91 to 0.93 - a consistent structural relationship.

Return for Risk

TWCUX vs. PLFMX — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.

TWCUX

TWCUX Risk / Return Rank: 17
TWCUX Sharpe Ratio Rank: 18
TWCUX Sortino Ratio Rank: 17
TWCUX Omega Ratio Rank: 17
TWCUX Calmar Ratio Rank: 15
TWCUX Martin Ratio Rank: 17

PLFMX

PLFMX Risk / Return Rank: 61
PLFMX Sharpe Ratio Rank: 59
PLFMX Sortino Ratio Rank: 54
PLFMX Omega Ratio Rank: 56
PLFMX Calmar Ratio Rank: 61
PLFMX Martin Ratio Rank: 73

The rank (0–100) shows how this investment's returns compare to the risk taken. Higher = better. Based on the past 12 months of data, combining Sharpe, Sortino, and other metrics used by quantitative funds and institutional investors.

TWCUX vs. PLFMX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Ultra Fund (TWCUX) and Principal LargeCap S&P 500 Index Fund (PLFMX). Risk-adjusted metrics are performance indicators that assess an investment's returns in relation to its risk, enabling a more accurate comparison of different investment options.

Values are calculated on a 1-year rolling basis and updated daily. Risk-adjusted metrics are more stable over longer periods — use the period switch above to explore them.

	TWCUX	PLFMX	Difference
Sharpe ratio: Return per unit of total volatility	1.15	2.09	-0.94
Sortino ratio: Return per unit of downside risk	1.61	2.83	-1.21
Omega ratio: Gain probability vs. loss probability	1.20	1.38	-0.17
Calmar ratio: Return relative to maximum drawdown	1.26	2.89	-1.63
Martin ratio: Return relative to average drawdown	4.28	13.00	-8.72

TWCUX vs. PLFMX - Sharpe Ratio Comparison

The current TWCUX Sharpe Ratio is 1.15, which is lower than the PLFMX Sharpe Ratio of 2.09. The chart below compares the historical Sharpe Ratios of TWCUX and PLFMX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Drawdowns

TWCUX vs. PLFMX - Drawdown Comparison

The maximum TWCUX drawdown since its inception was -62.11%, which is greater than PLFMX's maximum drawdown of -55.62%. Use the drawdown chart below to compare losses from any high point for TWCUX and PLFMX.

Drawdown Indicators

	TWCUX	PLFMX	Difference
Max Drawdown Largest peak-to-trough decline	-62.11%	-55.62%	-6.49%
Max Drawdown (1Y) Largest decline over 1 year	-15.72%	-9.00%	-6.72%
Max Drawdown (3Y) Largest decline over 3 years	-24.86%	-18.83%	-6.03%
Max Drawdown (5Y) Largest decline over 5 years	-35.23%	-24.91%	-10.32%
Max Drawdown (10Y) Largest decline over 10 years	-35.23%	-33.80%	-1.43%
Current Drawdown Current decline from peak	-5.73%	-1.74%	-3.99%
Average Drawdown Average peak-to-trough decline	-16.79%	-9.98%	-6.81%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.62%	2.00%	+2.62%

Volatility

TWCUX vs. PLFMX - Volatility Comparison

American Century Ultra Fund (TWCUX) has a higher volatility of 6.51% compared to Principal LargeCap S&P 500 Index Fund (PLFMX) at 4.68%. This indicates that TWCUX's price experiences larger fluctuations and is considered to be riskier than PLFMX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	TWCUX	PLFMX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.51%	4.68%	+1.83%
Volatility (6M) Calculated over the trailing 6-month period	13.51%	9.85%	+3.66%
Volatility (1Y) Calculated over the trailing 1-year period	17.27%	12.50%	+4.77%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.69%	17.01%	+5.68%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.16%	17.54%	+4.62%

TWCUX vs. PLFMX - Expense Ratio Comparison

TWCUX has a 0.93% expense ratio, which is higher than PLFMX's 0.72% expense ratio.

Dividends

TWCUX vs. PLFMX - Dividend Comparison

TWCUX's dividend yield for the trailing twelve months is around 11.15%, more than PLFMX's 2.20% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PLFMX Principal LargeCap S&P 500 Index Fund	2.20%	2.41%	3.77%	3.62%	2.28%	13.02%	7.02%	3.28%	6.80%	6.44%	2.66%	2.07%
TWCUX American Century Ultra Fund	11.15%	11.57%	3.58%	6.09%	7.42%	6.78%	2.80%	4.27%	8.24%	5.85%	4.58%	5.21%

Frequently Asked Questions

Can I hold both TWCUX and PLFMX in my portfolio?

With a correlation of 0.92, TWCUX and PLFMX move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.

Which is riskier, TWCUX or PLFMX?

TWCUX has higher volatility (6.51%) compared to PLFMX (4.68%). In terms of maximum drawdown, TWCUX dropped -62.11% vs PLFMX's -55.62%.

Which has better risk-adjusted returns?

PLFMX currently has the higher Sharpe Ratio (2.09 vs 1.15), meaning it's delivered slightly more return per unit of risk over the trailing 12 months. However, this ranking shifts over time - use the Risk/Return Score above for a more comprehensive view that combines Sharpe, Sortino, and other measures used by quantitative funds.